class Base{
    public int a;
    public int b;
    public void testA(){
        System.out.println("base:testA");
    }
    public void testB(){
        System.out.println("base:testB");
    }
}
public class Derived extends Base{
    public boolean a;
    public int c;
    public int d;
    public void testA(int a){
        System.out.println("Derived:testA"+a);
    }
    public void testB(){
        System.out.println("Derived:testB");
    }
    public void methodC(){
        c = 101; // 等价于： this.b = 101;
        super.a = 200;
        super.b = 201;
        testA();
        testA(20);
        testB();
        super.testB();
    }
}
